Impact of the tumor microenvironment on survival in anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is a highly aggressive malignancy characterized by nearly 100% mortality and significant therapeutic challenges. This study investigated the tumour microenvironment (TME) in ATC, focusing on immune checkpoint molecules (PD-L1/PD-1), tumour-associated macrophages (TAMs), and E-cadherin expression. A retrospective cohort of 22 ATC patients treated at a tertiary care centre in India, between January 2017 and August 2022, was analysed. Immunohistochemical evaluation revealed PD-L1 expression in 68.2% of cases, with a median tumour proportion score (TPS) of 50. PD-1 expression was limited to inflammatory cells. E-cadherin loss was observed in over 69% of cases, suggesting disrupted cell adhesion. TAM infiltration was elevated in 58.8% of patients and correlated significantly with PD-L1 expression (p = 0.02). Survival analysis demonstrated a significantly lower survival in patients with a high TAM density (0.015). Although not significant but patients expressing PD-L1 had a mean survival of 2.4 months compared to 4.1 months for those without PD-L1 expression (p 0.129). Similarly, high PD-1 expression in inflammatory cells and E cadherin expression in tumor cells correlated with poorer outcomes. These findings underscore the critical role of immune markers within the TME in influencing ATC prognosis. The findings highlight the potential of targeted immunotherapeutic strategies to improve outcomes in ATC. Further research is warranted to clarify the predictive value of these markers in guiding treatment approaches.